2 Unix SMB/CIFS implementation.
3 low level tdb backup and restore utility
4 Copyright (C) Andrew Tridgell 2002
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
22 This program is meant for backup/restore of tdb databases. Typical usage would be:
24 when Samba shuts down cleanly, which will make a backup of all the local databases
25 to *.bak files. Then on Samba startup you would use:
27 and this will check the databases for corruption and if corruption is detected then
28 the backup will be restored.
30 You may also like to do a backup on a regular basis while Samba is
31 running, perhaps using cron.
33 The reason this program is needed is to cope with power failures
34 while Samba is running. A power failure could lead to database
35 corruption and Samba will then not start correctly.
37 Note that many of the databases in Samba are transient and thus
38 don't need to be backed up, so you can optimise the above a little
39 by only running the backup on the critical databases.
44 #include "system/locale.h"
45 #include "system/time.h"
46 #include "system/filesys.h"
47 #include "system/wait.h"
56 static struct tdb_logging_context log_ctx
;
58 #ifdef PRINTF_ATTRIBUTE
59 static void tdb_log(struct tdb_context
*tdb
, enum tdb_debug_level level
, const char *format
, ...) PRINTF_ATTRIBUTE(3,4);
61 static void tdb_log(struct tdb_context
*tdb
, enum tdb_debug_level level
, const char *format
, ...)
66 vfprintf(stdout
, format
, ap
);
71 static char *add_suffix(const char *name
, const char *suffix
)
74 int len
= strlen(name
) + strlen(suffix
) + 1;
75 ret
= (char *)malloc(len
);
77 fprintf(stderr
,"Out of memory!\n");
80 snprintf(ret
, len
, "%s%s", name
, suffix
);
84 static int copy_fn(TDB_CONTEXT
*tdb
, TDB_DATA key
, TDB_DATA dbuf
, void *state
)
86 TDB_CONTEXT
*tdb_new
= (TDB_CONTEXT
*)state
;
88 if (tdb_store(tdb_new
, key
, dbuf
, TDB_INSERT
) != 0) {
89 fprintf(stderr
,"Failed to insert into %s\n", tdb_name(tdb_new
));
97 static int test_fn(TDB_CONTEXT
*tdb
, TDB_DATA key
, TDB_DATA dbuf
, void *state
)
103 carefully backup a tdb, validating the contents and
104 only doing the backup if its OK
105 this function is also used for restore
107 static int backup_tdb(const char *old_name
, const char *new_name
,
108 int hash_size
, int nolock
, bool readonly
)
111 TDB_CONTEXT
*tdb_new
;
116 tmp_name
= add_suffix(new_name
, ".tmp");
118 /* stat the old tdb to find its permissions */
119 if (stat(old_name
, &st
) != 0) {
125 /* open the old tdb */
126 tdb
= tdb_open_ex(old_name
, 0,
127 TDB_DEFAULT
| (nolock
? TDB_NOLOCK
: 0),
128 O_RDWR
, 0, &log_ctx
, NULL
);
130 printf("Failed to open %s\n", old_name
);
135 /* create the new tdb */
137 tdb_new
= tdb_open_ex(tmp_name
,
138 hash_size
? hash_size
: tdb_hash_size(tdb
),
140 O_RDWR
|O_CREAT
|O_EXCL
, st
.st_mode
& 0777,
149 if (tdb_lockall_read(tdb
) != 0) {
150 printf("Failed to obtain read only lock on old tdb\n");
157 } else if (tdb_transaction_start(tdb
) != 0) {
158 printf("Failed to start transaction on db\n");
166 /* lock the backup tdb so that nobody else can change it */
167 if (tdb_lockall(tdb_new
) != 0) {
168 printf("Failed to lock backup tdb\n");
178 /* traverse and copy */
180 count1
= tdb_traverse_read(tdb
,
184 count1
= tdb_traverse(tdb
,
188 if (count1
< 0 || failed
) {
189 fprintf(stderr
,"failed to copy %s\n", old_name
);
197 /* close the old tdb */
200 /* copy done, unlock the backup tdb */
201 tdb_unlockall(tdb_new
);
203 #ifdef HAVE_FDATASYNC
204 if (fdatasync(tdb_fd(tdb_new
)) != 0) {
206 if (fsync(tdb_fd(tdb_new
)) != 0) {
209 fprintf(stderr
, "failed to fsync backup file\n");
212 /* close the new tdb and re-open read-only */
214 tdb_new
= tdb_open_ex(tmp_name
,
220 fprintf(stderr
,"failed to reopen %s\n", tmp_name
);
227 /* traverse the new tdb to confirm */
228 count2
= tdb_traverse(tdb_new
, test_fn
, NULL
);
229 if (count2
!= count1
) {
230 fprintf(stderr
,"failed to copy %s\n", old_name
);
237 /* close the new tdb and rename it to .bak */
239 if (rename(tmp_name
, new_name
) != 0) {
251 verify a tdb and if it is corrupt then restore from *.bak
253 static int verify_tdb(const char *fname
, const char *bak_name
)
259 tdb
= tdb_open_ex(fname
, 0, 0,
260 O_RDONLY
, 0, &log_ctx
, NULL
);
262 /* traverse the tdb, then close it */
264 count
= tdb_traverse(tdb
, test_fn
, NULL
);
268 /* count is < 0 means an error */
270 printf("restoring %s\n", fname
);
271 return backup_tdb(bak_name
, fname
, 0, 0, 0);
274 printf("%s : %d records\n", fname
, count
);
280 see if one file is newer than another
282 static int file_newer(const char *fname1
, const char *fname2
)
284 struct stat st1
, st2
;
285 if (stat(fname1
, &st1
) != 0) {
288 if (stat(fname2
, &st2
) != 0) {
291 return (st1
.st_mtime
> st2
.st_mtime
);
294 static void usage(void)
296 printf("Usage: tdbbackup [options] <fname...>\n\n");
297 printf(" -h this help message\n");
298 printf(" -s suffix set the backup suffix\n");
299 printf(" -v verify mode (restore if corrupt)\n");
300 printf(" -n hashsize set the new hash size for the backup\n");
301 printf(" -l open without locking to back up mutex dbs\n");
302 printf(" -r open with read only locking\n");
305 int main(int argc
, char *argv
[])
313 bool readonly
= false;
314 const char *suffix
= ".bak";
316 log_ctx
.log_fn
= tdb_log
;
318 while ((c
= getopt(argc
, argv
, "vhs:n:lr")) != -1) {
330 hashsize
= atoi(optarg
);
348 for (i
=0; i
<argc
; i
++) {
349 const char *fname
= argv
[i
];
352 bak_name
= add_suffix(fname
, suffix
);
355 if (verify_tdb(fname
, bak_name
) != 0) {
359 if (file_newer(fname
, bak_name
) &&
360 backup_tdb(fname
, bak_name
, hashsize
,
361 nolock
, readonly
) != 0) {